Long-Living GHz Vibrations in Opal-Based Hypersonic Crystals

A. S. Salasyuk ； A. V. Scherbakov ； D. R. Yakovlev ； A. V. Akimov ； A. A. Kaplyanskii ； S. F. Kaplan ； S. A. Grudinkin ； A. V. Nashchekin ； A. B. Pevtsov ； V. G. Golubev ； T. Berstermann ； C. Brüggemann ； M. Bombeck ； M. Bayer

《Chinese Journal of Physics》 49卷1期 (2011/02) Pp. 56-62

並列摘要

We report experiments in which high-quality silica opal film is used as a three-dimensional hypersonic crystal in the GHz frequency range. We inject into the sample a broadband elastic wave packet by means of optical excitation of metal hypersound transducer and study the temporal evolution of GHz coherent vibrations monitoring the modulation of film reflectivity. Measurements carried out at different incident angles of probe beam allow us to determine that only coherent surface vibrations contribute to the measured modulation of reflectivity. This conclusion is supported by the long lifetime of surface vibrational modes with the frequency that matches a phononic band gap.